Taxonomic revision of the genus Hyperaulax Pilsbry, 1897 (Gastropoda, Stylommatophora, Odontostomidae)

Abstract

The genus Hyperaulax Pilsbry, 1897 comprises two living species endemic to the oceanic Fernando de Noronha Archipelago, off north-eastern Brazil. They are currently allocated in two subgenera, Hyperaulax s. str. and Bonnanius Jousseaume, 1900, belonging to the family Odontostomidae. Herein we present a taxonomic revision of these species, assessing their familiar allocation within Orthalicoidea, offering updated diagnoses and descriptions, figuring the type materials and further relevant specimens, and providing barcoding DNA sequences. We conclude that Bonnanius is a junior synonym of Hyperaulax, which is classified in Odontostomidae. The genus contains two valid species, H. ridleyi and H. ramagei, both endemic to Fernando de Noronha.

Molecular phylogeny of the Orthalicoidea land snails: Further support and surprises

“…Our study also includes two other genera in this family: Tomigerus Spix, 1827 and the island endemic Hyperaulax Pilsbry, 1897. The species in both genera have similarities in their shells that indicated their affinity and their sister-taxa relationship proposed by [ 10 ] is fully supported here ( Fig 3 ). Likewise, we propose here that the genera Biotocus Salgado & Leme, 1990 and the cave endemic Clinispira Simone & Casati, 2013, which have shells closely resembling Tomigerus [ 32 , 52 , 53 ], also belong in this resurrected family.…”

“… The * indicates species used as part of the outgroup. The † and the ‡ indicate, respectively, sequences from [ 10 , 12 ]. …”

“…In these cases, only 20 million generations were enough. The COI alignment was not used due to the known low resolution this marker provides to elucidate family level relationships within Orthalicoidea (e.g., [ 10 , 12 ]). Almost no inconsistencies were found, but some interesting differences are discussed below.…”

“…DNA sequences from a further 86 representatives of the Orthalicoidea were obtained Gen-Bank stemming from the works of [6,7], as well as [9][10][11][13][14][15][16][17] (Table 2). Representatives of Achatinidae and Strophocheilidae were included as outgroup to root the trees (Tables 1 and 2).…”

“…The limited taxon sampling, limited resolution and frequently poor branch support for phylogenetic splits has revealed some uncertainties in the taxonomic classification of the Orthalicoidea. Additional molecular studies published after [ 7 ], have usually focussed on more specific systematic problems, typically singling out a certain genus of interest (e.g., [ 8 ]: Bulimulus ; [ 9 ]: Clessinia ; [ 10 ]: Hyperaulax ; [ 11 ]: Placostylus ). Yet, no other study has aimed at improving the tree of the Orthalicoidea overall to facilitate a more objective classification of this group.…”